Apparatus and a method of inserting spinal implants is disclosed in which an intervertebral space is first distracted, a hollow sleeve having teeth at one end is then driven into the vertebrae adjacent that disc space. A drill is then passed through the hollow sleeve removing disc and bone in preparation...http://www.google.com.hk/patents/US6436098?utm_source=gb-gplus-share專利 US6436098 - Method for inserting spinal implants and for securing a guard to the spine
